code: def apply(
      self, key: str, window: CountWindow, inputs: Iterable[tuple]
  ):
      result = 0
      for i in inputs:
          result += i[0]
      return [(key, result)]
  
file_path: flink/flink-python/pyflink/examples/datastream/windowing/tumbling_count_window.py
imports: import sys
  import argparse
  from typing import Iterable
  from pyflink.datastream.connectors.file_system import FileSink, OutputFileConfig, RollingPolicy
  from pyflink.common import Types, Encoder
  from pyflink.datastream import StreamExecutionEnvironment, WindowFunction
  from pyflink.datastream.window import CountWindow
label_desc: Use image node_id 1 for calling the SumWindowFunction obj's underlying member method code with example usage: obj.apply(key, window, inputs) and returns: list